Dual gate field effect transistor based on two dimensional electron gases at SrTiO₃ surfaces

We fabricate dual gate field effect transistors (FETs) based on two dimensional electron gas (2DEG) at SrTiO₃ (STO) surfaces with high mobility as high as 20,000cm²V^-1s^-1. The channel conductivity is controlled by a side gate and a back gate. Both gates apply electric fields across STO crystalline, and are most efficient near ground state due to the quantum ferroelectricity of STO. Based on the dual-gate FET structure we made a performance-tunable logic NOT gate. The ON/OFF of the channel is switch by side gate logic input, whereas the switching performance is tunable by the back gate. The back gate voltage window depends on the power supply voltage of the device. On one hand, the window is wider at a higher power supply voltage. On the other hand, by carefull tuning the back voltage, the device can work with good performance at a lower power supply voltage. Our results provide an general approach to energy saving as well as decreasing Joule heat for cryogenic quantum computing.